Utilization of Clustered Regularly Interspaced Short Palindromic Repeats to Genotype Escherichia coli Serogroup O80.

Haiyan Yang,Jinzhao Long,Guangcai Duan,Liuyang Ou,Yuanlin Xi,Shuaiyin Chen,Yake Xu

doi:10.3389/fmicb.2020.01708

Abstract

The hypervariable nature of clustered regularly interspaced short palindromic repeats (CRISPRs) makes them valuable biomarkers for subtyping and epidemiological investigation of Escherichia coli. Shiga toxin-producing E. coli (STEC) serogroup O80 is one hybrid pathotype that is emerging recently in Europe and is involved in hemolytic uremic syndrome with bacteremia. However, whether STEC O80 strains can be genotyped using CRISPR has not been evaluated. In this study, we aimed to characterize the genetic diversity of 81 E. coli serogroup O80 isolates deposited in the National Center for Biotechnology Information databases using CRISPR typing and to explore the association between virulence potential and CRISPR types (CTs). A total of 21 CTs were identified in 80 O80 strains. CRISRP typing provided discrimination with variants of a single serotype, which suggested a stronger discriminatory power. Based on CRISPR spacer profiles, 70 O80:H2 isolates were further divided into four lineages (lineage LI, LII, LIII, and LIV), which correlated well with whole-genome single nucleotide polymorphisms typing and virulence gene profiles. Moreover, the association between CRISPR lineages and virulence gene profiles hinted that STEC O80:H2 strains may originate from O80:H19 or O80:H26 and that lineage LI may have been evolved from lineage LII. CT2 and CT13 were shared by human and cattle isolates, suggesting that there might be the potential transmission between cattle and human. Collectively, CRISPR typing is one technology that can be used to monitor the transmission of STEC O80 strains and provide new insights into microevolution of serogroup O80.

Highlights

Shiga toxin-producing Escherichia coli (STEC) is the major food-borne zoonotic pathogen related to both outbreaks and sporadic cases, representing a worldwide public health concern (Karmali, 2017)
The serogroup O157 contributes to most hemolytic uremic syndrome (HUS) cases of STEC infection, but other non-O157 serogroups are increasingly important in public health (Espie et al, 2008)
70 strains were positive for the H2 fliC gene, 8 strains were positive for the H26 fliC gene, and 3 strains were positive for the H19 fliC gene

Summary

Introduction

Shiga toxin-producing Escherichia coli (STEC) is the major food-borne zoonotic pathogen related to both outbreaks and sporadic cases, representing a worldwide public health concern (Karmali, 2017). STEC infection in humans can cause a series of gastrointestinal diseases ranging from mild to severe diarrhea. One subset of the STEC strains, called as enterohemorrhagic E. coli, is linked to CRISPR Typing of E. coli O80 life-threatening hemolytic uremic syndrome (HUS). Over 400 STEC serotypes have been detected in humans and animals, but only a small subset of serotypes is responsible for HUS cases (Delannoy et al, 2013). The serogroup O157 contributes to most HUS cases of STEC infection, but other non-O157 serogroups are increasingly important in public health (Espie et al, 2008)

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